1976—2024年黄河三角洲海岸线变化分析

    Analysis of shoreline changes in Yellow River Delta from 1976 to 2024

    • 摘要: 受自然过程和人类活动的影响,黄河三角洲海岸线始终处于快速变化之中。本文基于1976—2024年黄河口30 m空间分辨率(Landsat系列)与16 m空间分辨率(GF-1)的年际岸线位置数据,利用数字岸线分析系统(DSAS)探讨了48年来黄河三角洲海岸线动态演变规律及其对台风的响应。结果表明,黄河三角洲海岸线演变整体表现为淤进趋势,陆地面积增长为6.358 km2/a,同时呈现显著的阶段性特征,具体可划分为3个典型阶段:快速淤进阶段(1976—1988年,最大速率为1 825 m/a);整体蚀退阶段(1989—2008年,最大速率为-1 243 m/a);局部有效淤进阶段(2009年以后,2016—2024年现行河口淤进速率为320 m/a)。研究发现,入海水沙通量是岸线演变的主控因素,人类活动通过调节水沙季节性分配直接塑造冲淤格局,而极端事件在低泥沙背景下会显著放大侵蚀效应。此外,台风事件对岸线的影响表现出强烈的空间异质性,暴露岸段侵蚀剧烈,但部分区域因水沙补给展现恢复潜力。研究揭示了黄河三角洲岸线“阶段性不稳定、空间异质性强、局部具备恢复力”的综合响应特征,为该高动态三角洲的可持续管理和适应性调控策略制定提供了重要科学依据。

       

      Abstract: Shoreline evolution is a critical issue of coastal zone resource management and sustainable development. Influenced by both natural processes and human activities, the coastline of the Yellow River Delta (YRD) has persistently undergone rapid changes. We investigated the dynamic evolution patterns of the YRD coastline over the past 48 years (1976 to 2024) and its response to extreme weather events by using Landsat series and GF-1 satellite imagery of the YRD and the Digital Shoreline Analysis System (DSAS). Results demonstrate that the evolution of the YRD coastline showed a trend of sediment accretion by an average annual increase in land area of 6.358 km2. Furthermore, the evolution displays distinct phase-specific characteristics, which can be categorized into three typical stages: (1) Rapid deposition stage (1976 to 1988, maximum rate of 1825 m/a in coastline length); (2) The whole erosion stage (1989 to 2008, the maximum rate of 1243 m/a); (3) Local effective siltation stage (after 2009, the current estuary siltation rate from 2016 to 2024 was 320 m/a). The sediment flux into the sea was the dominant controlling factor of shoreline evolution. Human activities directly shaped the accretion-erosion pattern by regulating the seasonal distribution of water and sediment, while extreme events significantly promoted the erosion under low-sediment conditions. Moreover, the impact of extreme events on the coastline showed pronounced spatial heterogeneity: exposed shorelines experienced heavy erosion, and some areas demonstrated recovery potential due to sediment replenishment. We elucidated the comprehensive response characteristics of the YRD coastline, which was characterized by "phase-specific instability, strong spatial heterogeneity, and localized resilience". These findings provided an important scientific basis for sustainable management and adaptive regulation strategies for this highly dynamic delta.

       

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